Bear Dens in Coastal British Columbia

Helping Land Managers Identify and Retain Black Bear Dens

American black bears need large, old trees with cavities to survive the wet, cool conditions of winters in coastal British Columbia. Unfortunately, these large old trees are often lost during forest harvest operations, sometimes because field staff cannot easily tell which trees are dens. Using information collected over 25 years, Artemis Wildlife Consultants has developed training and tools to help forest licensees and their contractors identify and retain these critical wildlife habitat features within their operations. Learn about general bear ecology, how to differentiate bear dens from day beds, and different strategies for den retention and how the supply of dens affects bear populations.

Den Identification Workshops for foresters and field staff are available for delivery throughout coastal British Columbia. Please contact Helen Davis for more information or to schedule a workshop.

This manual is meant to help field crews identify winter dens used by black bears and grizzly bears in coastal British Columbia. Specifically, this manual provides information on types of dens, a brief description of how cavities that produce dens are formed in trees and characteristics of trees or excavations that field staff can use to identify potential dens. The final decision as to whether a tree or excavation is a bear den and worthy of protection should be made by a Qualified Professional whose scope of expertise includes bear ecology and den identification. As such, a great deal of responsibility lies with Qualified Professionals to identify these critical habitat elements.

If you are surveying for bear dens in coastal BC, please consider using our standardized field data form to help field crews collect information that will help development and operations foresters work towards retaining the structure within their operations. The Avenza Maps® schema for entering den data has many fields that will aid in future analyses of what coastal bears are selecting for when choosing den sites. The Avenza Maps® schema automatically records the date and coordinates (in latitude and longitude and UTM Easting and Northing, but not Zone) of “den pins” dropped using the schema.

American black bears (Ursus americanus) require suitable winter den sites to provide security and cover to successfully survive the critical winter denning period. Dens are reused intermittently over decades, if not longer, and may be used by successive bears. On Vancouver Island, winter dens used by black bears have been found in or beneath large diameter (mean of hollow tree dens = 160 cm) trees or structures derived from trees (i.e., logs, root boles and stumps).

Current and historic land management activities in coastal forests have affected the supply of these critical element-level features. Most significantly, forest harvesting has removed many large trees that form these den structures. Furthermore, these large structures are not replaced during forest rotations because the new crops of trees are not allowed to grow to sufficient size for replacement dens to develop. Despite the knowledge that these habitat features are critical to the over-winter survival of black bears, no regulatory protection is in place for these critical structures in BC.

The objectives of this project are two-fold. First, this project aims to attempt to mitigate losses of denning opportunities by enhancing natural structures by creating entrances to cavities in existing old growth trees or large legacy stumps that have hollow centres. Second, this project is evaluating whether bears will use artificial structures specifically designed to compensate for the loss of natural structures. Twenty-one dens (9 in natural structures, 12 in artificial structures) were created in 2014-2015 and were monitored with cameras until 2019. Initial monitoring found bears investigating both types of structures extensively and in between 2017-2020 one stump that had been turned into a den (photo above) was used as a den by a black bear! See video (https://www.youtube.com/watch?v=AKGcz7CC-fA) of creation of den and bear pulling plants inside for bedding. Goals of the project include 1) increased awareness by forest companies of the need for retention of bear den structures and possibilities for den creation in coastal BC, and, 2) increased awareness by government policy makers of the need for regulation to protect these critical forest elements.